1. Field of the Invention
The present invention relates generally to apparatus for harnessing and utilizing gravitational forces and, more particularly, as such forces relate to an automatic pneumatic tire pressurizing and regulating apparatus attachable to a vehicle wheel and operated by the rolling motion thereof.
2. Description of the Prior Art
It is believed that there is no known mechanical application of such kinds of apparatuses having a displacement type air pump including an oscillating unitary free piston mass which is antifrictionally supported for reciprocation and principally utilizes gravitational forces produced at location(s) eccentric from an axis of rotation of a body experiencing rolling translation while also utilizing centrifugal forces and minimizing the negative effects thereof. Such forces are created at all points eccentric from the axis of rotation of a rolling vehicle wheel, for example. Hence, an advantage exists for an apparatus for harnessing and utilizing gravitational and centrifugal forces generated at locations eccentric from an axis of rotation of a rolling body, particularly a vehicle wheel or the like, wherein primarily the gravitational forces are used to both position a means for effecting a working stroke and for causing the operation thereof, and wherein centrifugal forces that may be present are positively utilized but not principally relied upon, do not prevent the effective utilization of the gravitational forces. Such an apparatus could be mounted to a vehicle wheel and advantageously used, inter alia, to operate a pump mechanism for pressuring and regulating the pressure of a pneumatic vehicle tire.
It is further believed that no such tire pressurizing and regulating apparatus is available which can be tuned by preselecting compression ratio parameters such as piston mass, piston stroke length, piston face area, piston blow-by, piston shape, piston friction, cylinder volume and intake and output orifice size, whereby the piston may be caused to oscillate to effect working strokes due to gas compression spring effects to respectively initiate piston movement in the opposite direction even at wheel rotation velocities which are in excess of velocities whereby gravity is no longer effective or sufficient to effect working strokes of the piston.
Other wheel mounted apparatuses have been proposed for automatically controlling vehicle tire pressure. An example of such an apparatus is described in U.S. Pat. No. 4,349,064 wherein one or more centrifugally operated dual-chamber piston and cylinder pumps are secured to the rim of a vehicle wheel interiorly of a surrounding pneumatic tire. Upon repeated cycles of acceleration and deceleration of the rotation of the vehicle wheel, centrifugal force causes the piston to pump air into the tire until predetermined tire pressure is achieved where upon the pump then serves to maintain the predetermined pressure. Such a system requires permanent attachment of the pump to the rim of the wheel, modification of the wheel structure, and removal of the tire in order to service or replace the pump.
Similar centrifugally operated pump/regulators are described in U.S. Pat. No. 4,570,691 wherein the regulator is again secured to the wheel rim interiorly of the tire and in U.S. Pat. No. 4,651,792 wherein the pump is secured to the interior of the tire. These pump/regulators suffer from disadvantages similar to those associated with U.S. Pat. No. 4,349,064. Furthermore, all of the aforementioned pump/regulators operate exclusively on the principal of harnessing and utilizing centrifugal force, a force which is not cyclic so that the pump/regulators must employ a design to operate on other variables or introduced forces.
The inflating device described in U.S. Pat. No. 1,643,945 does appear to take advantage of gravitational forces. However, the free floating piston mechanism is not unitary in construction and cannot be realized or even adapted to take advantage of piston gas compression restoring forces in order to make the pump operative even at wheel rotational velocities above the point where working strokes can no longer be effected by gravity alone.
A double action automatic tire inflation pump is illustrated in U.S. Pat. No. 2,055,983. This inflation device is attached essentially to the wheel and cannot take principal advantage of the effects of gravitation and further supports the entire free floating piston mass with sliding frictional engagement between the pistons and piston cylinders. Additionally, no teachings are suggested whereby the inflation device might be tuned in order to make the pump operable even after such time that the pump would normally be absolutely inoperative due to excessive wheel rotational velocities.
U.S. Pat. No. 4,307,997 also illustrates another double action free piston inertia pump. It additionally does not take full advantage of the effects of gravitational forces upon the pump and it does not teach or suggest tuning of the pumping device by taking advantage of gas compression spring effect created by the opposing double action pistons in order to make the device operative even at rotational velocities in excess of those at which the pump will normally not operate, even though this reference does teach the use of a gas spring effect to initiate movement in the opposite direction and to cushion the piston impact.
It is an object of the present invention to provide apparatus for harnessing and utilizing gravitational forces generated at a location eccentric from the axis of rotation of a vehicle wheel for pressurizing and regulating the pressure of a pneumatic tire carried by the wheel, wherein primarily gravitational forces are used to both position a pressure creating means in an operating position and for effecting operation thereof, and wherein the apparatus will not be adversely affected by negative effects of centrifugal forces.
It is a further object of the present invention to provide a readily accessible pneumatic tire pump/regulator which is releasably attachable to an existing wheel rim structure, such as the wheel valve stem universally employed today, and which will be of a very small size and weight, yet capable of producing a relatively high effective pressure.
Another object of the present invention is to provide for a pneumatic tire pump/regulator to be mounted on the wheel vane stem of an inflatable vehicle tire, in which the pump/regulator is tangentially positioned relative to the path of rotation of the tire and stem and capable of providing two pumping strokes per revolution of the wheel.
It is another object of the present invention to provide a double action piston cylinder device attachable to the valve stem of a pneumatic tire, wherein the piston is arranged tangentially to the rotational path of the stem, and wherein the piston will be positioned primarily by gravitational force and some centrifugal force generated by the system in two working stroke positions during a given rotation of the tire, and when so positioned the piston will be displaced primarily by gravity with some positive centrifugal force influence to effect the two working strokes.
It is a farther object of the present invention to provide a pneumatic tire pump/regulator requiring no modification of either the vehicle wheel or the pneumatic tire.
A still further object of the present invention is to provide a pneumatic tire pump/regulator having a piston cylinder assembly, wherein the piston thereof has a central member and two similar axially extending opposed end members, and wherein the central member possesses substantially the greater part of the mass of the piston.
Another object of the present invention is to support the enlarged central piston member of the double action piston assembly itself for antifrictional reciprocation in its housing. This is preferably accomplished with maximum antifrictional capabilities such as by spaced rotatable bearing elements, or less expensively with oil impregnated bronze slide bearings.
Yet another object of the present invention is to provide such a pneumatic tire pump/regulator wherein the compression ratio parameters of the pump (such as piston mass, piston stroke length, piston face area, piston blow by, piston shape, piston friction, cylinder volume, and intake and output orifice size) may be preselected for tuning the pump whereby the double action piston assembly is cause to oscillate to effect working strokes due to the gas compression spring effect of the double acting piston-cylinder arrangements or combinations, to respectively initiate movement in the opposite directions, even at wheel rotation velocities in excess of which gravity can no longer provide sufficient effect or working strokes.
It is a further object to provide a pneumatic tire pump/regulator wherein the tire maintenance pressure is controlled by controlling the compression ratio of the pump.
Still other objects and advantages of the present invention will become more apparent in light of the attached drawings and written description of the invention presented hereinbelow.